Merge Sort and Insertion Sort Programs Implement merge sort and insertion sort t
ID: 3872636 • Letter: M
Question
Merge Sort and Insertion Sort Programs
Implement merge sort and insertion sort to sort an array/vector of integers. Implement the algorithms in C++, name one program “mergesort” and the other “insertsort”. Your programs should be able to read inputs from a file called “data.txt” where the first value of each line is the number of integers that need to be sorted, followed by the integers.
Example values for data.txt:
4 19 2 5 11
8 1 2 3 4 5 6 1 2
The output will be written to files called “merge.out” and “insert.out”.
For the above example the output would be:
2 5 11 19
1 1 2 2 3 4 5 6
Explanation / Answer
MERGE SORT
#include<stdlib.h>
#include<stdio.h>
#include<string.h>
FILE *fp,*fpw;
void merge(int arr[], int l, int m, int r)
{
int i, j, k;
int n1 = m - l + 1;
int n2 = r - m;
int L[n1], R[n2];
for (i = 0; i < n1; i++)
L[i] = arr[l + i];
for (j = 0; j < n2; j++)
R[j] = arr[m + 1+ j];
i = 0;
j = 0;
k = l;
while (i < n1 && j < n2)
{
if (L[i] <= R[j])
{
arr[k] = L[i];
i++;
}
else
{
arr[k] = R[j];
j++;
}
k++;
}
while (i < n1)
{
arr[k] = L[i];
i++;
k++;
}
while (j < n2)
{
arr[k] = R[j];
j++;
k++;
}
}
void mergeSort(int arr[], int l, int r)
{
if (l < r)
{
int m = l+(r-l)/2;
mergeSort(arr, l, m);
mergeSort(arr, m+1, r);
merge(arr, l, m, r);
}
}
void printArray(int A[], int size)
{
int i;
for (i=0; i < size; i++)
fprintf(fpw,"%d ", A[i]);
fprintf(fpw," ");
}
int main()
{
int arr[1000] = {0};
int arr_size =0;
int data;
char file1[20];
strcpy(file1,"data.txt");
fp = fopen(file1,"r+");
if (fp == NULL) // if file not opened return error
{
perror("Unable to open file");
return -1;
}
else
{
fscanf (fp, "%d", &data);
arr[arr_size]=data;
arr_size++;
while (!feof (fp))
{
fscanf (fp, "%d", &data);
arr[arr_size]=data;
arr_size++;
}
}
char file2[20];
strcpy(file2,"merge.out");
fpw = fopen(file2,"w");
if (fpw == NULL) // if file not opened return error
{
perror("Unable to create file");
return -1;
}
fprintf(fpw,"Given array is ");
printArray(arr, arr_size);
mergeSort(arr+1, 0, arr[0]-1);
fprintf(fpw," Sorted array Using MERGE SORT is ");
printArray(arr, arr_size);
fclose(fpw);
fpw=NULL;
fp=NULL;
return 0;
}
INSERTION SORT
#include <stdio.h>
#include <math.h>
#include<string.h>
FILE *fp,*fpw;
void insertionSort(int arr[], int n)
{
int i, key, j;
for (i = 1; i < n; i++)
{
key = arr[i];
j = i-1;
while (j >= 0 && arr[j] > key)
{
arr[j+1] = arr[j];
j = j-1;
}
arr[j+1] = key;
}
}
void printArray(int arr[], int n)
{
int i;
for (i=0; i < n; i++)
fprintf(fpw,"%d ", arr[i]);
fprintf(fpw," ");
}
int main()
{
int arr[1000] = {0};
int arr_size =0;
int data;
char file1[20];
strcpy(file1,"data.txt");
fp = fopen(file1,"r+");
if (fp == NULL) // if file not opened return error
{
perror("Unable to open file");
return -1;
}
else
{
fscanf (fp, "%d", &data);
arr[arr_size]=data;
arr_size++;
while (!feof (fp))
{
fscanf (fp, "%d", &data);
arr[arr_size]=data;
arr_size++;
}
}
char file2[20];
strcpy(file2,"insert.out");
fpw = fopen(file2,"w");
if (fpw == NULL) // if file not opened return error
{
perror("Unable to create file");
return -1;
}
fprintf(fpw,"Given array is ");
printArray(arr, arr_size);
insertionSort(arr+1, arr[0]-1);
fprintf(fpw," Sorted array Using INSERT SORT is ");
printArray(arr, arr_size);
fclose(fpw);
fpw=NULL;
fp=NULL;
return 0;
}